Typical known industrial machines include a measuring machine that measures an object by a relative movement of a contact piece with respect to the object, and a working machine that machines an object by a relative movement of a working tool with respect to the object (see, for instance, Patent Literature 1: JP 2012-078214 A).
A machine of Patent Literature 1 includes a probe, a drive mechanism configured to three-axially move the probe, and an operation unit including an operation lever for operating the drive mechanism. An operator of such a coordinate measuring machine operates the drive mechanism using the operation lever of the operation unit to three-dimensionally move the probe with respect to an object.
In a typical coordinate measuring machine as described above, an operation command is immediately outputted to the drive mechanism in response to detection of, for instance, a tilt of the operation lever. Thus, for instance, if the arm or the like of the operator or any other worker accidentally touches the operation lever by carelessness, or if the operator accidentally lets the operation unit fall down to apply an external force to the operation lever, a motion of the drive mechanism unintended by the operator would be caused. Such an unintended motion may cause collision between the contact piece and the object, damaging the contact piece or the object.